The Solo – Single Dose Espresso Grinder

The Solo – Single Dose Espresso Grinder

Lee Brooks

Bella Barista is the authorised UK retailer for this grinder, it comes under a few different names in Europe. It is a single dosing extra low retention (ELR) grinder that uses flat 64mm Italmill burrs. The mounting points on the burr carriers are fully compatible with those for a Mazzer Mini E, or Super Jolly, should you wish to source alternate burrs. A full metal bodied construction in aluminium alloy with 2 contrasting colours and finishes. Wrapped to give different colours and finishes. The grinder I have is a very early production version in “Aluminium finish”, but it’s still a wrap (however, I believe permanent with adhesive). UK colours will initially be, Carbon Fibre, Matt Black and White. Note: If re-wrapping, I would recommend doing this over the existing wrap!


I have had this grinder for some months now, it is built in China and unlike a few Chinese grinders I have seen this is actually pretty good, definitely well made and least the standard of similarly priced grinders from Italy…if not exceeding their standard. I think it’s fair to say it’s not the most exciting looking grinder and won’t win any design awards but from a functional perspective it works really well.

I’ve used it to make all types of drinks including pour over and on a few different types of machines (pumped and spring lever). It has performed really well in all cases. It has more than met my expectations of a 64mm flat burr grinder. The inclined orientation allows much of the coffee out of the burr chamber. This coupled with the well shaped sweep arms, mebrane declumper, highly internally polished exit chute and puffer means retention and exchange within the grinder is very low indeed. There is definitely no need to purge if using the grinder as designed.

Some Definitions

  • There are 3 key areas that we should care about in a grinder, in addition to grind quality
  • Total Retention
  • Dose Consistency
  • Exchange

Total Retention

All grinds are removed, weighed and come from entire “grind path” of a grinder after it has ground at least 2 or 3 double shots of coffee and dose consistency normalises.

Dose Consistency

Is the weight of coffee in vs. the weight of coffee out. Ideally, you want this to be as close to identical as possible e.g 20g beans in = 20g ground coffee out, every time you grind. In practice, this is impossible, because of measurement error, static and exchange variance.


You might put 20g into a grinder and get 20g out….but what weight of that output is stale coffee from the previous grind? This number is also variable as oily coffee is stickier and may show more exchange than non-oily coffee. When *single dosing a grinder. The exchange figure cannot be higher than the total retention, or less than the dose consistency variation.

How the solo performed

My figures below are for the coffees I used…yours may vary

  • Retention = less than 1g
  • Dose consistency = less than 0.2g variance
  • Exchange = estimated at less than 0.3g

It is a competent single dose grinder that in my opinion requires no purging, changes in grind settings are immediately reflected in the next grind.

Build Quality

The build quality is good, it’s all metal alloy with 3 finishes combined in a single grinder:

  • Aluminium alloy (mid polished)
  • Aluminium alloy wrapped
  • Aluminium alloy black textured finish

The grinder is heavy, approximately 7kg, seems well made. the burr carriers are well machined. The top burr carrier has 3 raised mounting points for the burr…the bottom carrier mounting points are flush with the carrier, burr removal/replacement is easy enough.

The top burr carrier is pushed by the adjustment ring and moves up/down to adjust grind fineness. This carrier has a tube which slides inside the tube holding the lower burr and centralises the top carrier. There is an O ring on the tube of the top burr carrier which helps seal and centralise the system without slack (and potential lateral movement, or binding) that would exist without an O ring. O ring tolerances are pretty good and arguably the O ring might wear slightly over time. Although this is going to be a very long time considering the limited movement of the carrier even over a decade of use. I had considered lubrication, something like Dow corning 111 would leave a residue that would attract coffee grinds and likely be non optimal. A specialist food safe dry lube would be recommended…which I happen to have (Action Can Dry PTFE).

I particularly liked the fact that the motor area was completely sealed from the top of the grinder, this means no coffee going down in amongst the electronics, or motor area, a problem in some grinders. I’m not really concerned about overheating in domestic use and the aluminium alloy case will readily radiate heat away in the domestic environment.

There is single on/off, illuminated non latching switch towards the base of the grinder along the midpoint , It would have been nice if a second portafilter non latching push switch had been added. Pushing the switch turns the grinder on and pushing again turns it off, in addition a timeout will switch the grinder off after about 40 seconds.


It’s a flat burr grinder using 64mm Italmill burrs. The performance was as expected for any 64mm grinder with respect to grind quality. The burr quality was good, the grind speed just under 1g per second, again normal when considering the burr feed angle and single dosing.

In use the grinder is not particularly quiet, noise is on a par with other commercial 64mm grinders…

Grind quality was at least equal to that of other common 64mm burr grinders on the market. Adjustability was excellent with a wide and easy to move adjuster with marks that lined up against a coffee bean symbol as an indicator marker. I would have liked the coffee bean symbol to have been in a contrasting colour rather than black on black. I actually highlighted mine with a white chalk marker and will probably upgrade it to a gold, or silver metallic pen highlight, when I get around to it.

Each mark on the adjuster ring indicates a 12.5 micron movement of the burs (further together/apart). The grinder is stepless and adjustments of 1/2 a mark or less are easy to make giving an affective repeatable resolution of less than 7 microns. To put this into perspective a human red blood cell has a diameter of 8 Micron. So it’s adjustable to a very fine degree indeed…important when dialling in that espresso exactly.

Coffee (espresso, americano, pour over) produced with this grinder was excellent and again exactly what one would expect from a well set up and accurate 64mm grinder with decent burrs. It’s fair to say that output benefits from stirring the grinds to mix them, because the very nature of a diminishing load of beans in a single doser means a grind variance from fine to coarse. This results in a distribution that benefits from being mixed. I did try shots without it stirring the grinds before tamping and definitely experienced more problems than when the grinds are stirred.

I have included a video of the same coffee made at 3 different times, 2 I didn’t stir and the other I used a portafilter ring and stirred.  The other option is to use the grind cup, and if you don’t like the plastic one, get a cheap steel one from Amazon etc. The action of inverting the grinds helps to mix them

Note: always better to use the bellows once the coffee has finished coming out of the spout.

Below are some videos of shots from the grinder

Burr Options, cleaning and changing burrs

The solo uses a standard 64mm burr set with good quality Steel burrs. TiN (Titanium Nitride) coated burrs are available and any 64mm Mazzer burr for a super Jolly and Mazzer Mini would seem to fit OK as well. So many burr options are available if you don’t like the standard burrs.

I did install the TiN coated burrs. They will wear better (last longer) than steel burrs, and I don’t know how long but I would estimate at least 50% more burr life. The TiN coasting process does include burr preparation that will reduce break in time a little. Apart from that I saw no material difference in the cup, between the TiN burrs and the standard steel burrs that come with the grinder. I would recommend saving your money and sticking with the standard burr option

Cleaning is an easy process, you simply unscrew the collar and vacuum out the grinder. I would recommend marking the upper burr carrier and replacing it in the same position….or the position you find gives the best performance. You may find that a different position may benefit performance, or reduce certain minor amounts of axial alignment when you get to the burr touching point.

Touching Point

The burrs will not always touch at the zero point and I recommend finding and noting your burr touching point on the marker ring. You could use a chalk marker or a small piece of coloured tape for this. This is because the marker ring is not itself moveable and is stuck down to the adjustment collar.

The procedure for finding the burr touching point is the same on all flat burr grinders where you can reach the central burr spindle.

  • Tighten the collar down most of the way
  • Continue tightening in stages and spin the driven burr with your fingers until you feel burrs have touched
  • As the burrs touch you will feel a glide…back off a little (1 mark)
  • Mark the indicator ring at that point as the burr touching point (lined up with the slit in the coffee bean, which by now you will have highlighted in white..)

The burr change process was simple and comparable to other flat burr grinders

Nothing difficult or unusual to change the burrs in this grinder…A little video with me playing about with the burrs when changing them.


Overall I liked the grinder a lot. It’s a change to see some reasonable quality grinders coming out of China, especially with burrs manufactured in Europe. I certainly wouldn’t trust or rate burrs manufactured in china at this time. The grinder is simple to use, doesn’t require heavy puffing of the bellows to get all the grinds out. I suspect the inclined burr chamber helps a lot with this and is becoming a feature more commonly seen on grinders.

It’s not as refined as other much more expensive 64mm grinders, but the performance equals or betters them especially with respect to retention a, single dosing and exchange, with no purging required.

Are there better grinders, yes, are there better flat burr grinders for this sort of money…absolutely not, you would have to pay a lot more. If you want a single dosing, extra low retention, 64mm flat burr grinder…the Solo is compelling at it’s price point. In fact the performance and quality of grind is exceptional for the money.

This is a review of my experiences after using the grinder for over 2 months, results and guidance on how they were achieved. It does not constitute an official instruction on how to use or maintain the grinder. Manufacturer’s instructions and safety warnings must always be observed and may be subject to change or update at any time.

Author: Dave C